ABSTRACT A new xanthone: mangostanaxanthone VIIII [1,3,5,6,7-pentahydroxy-2-(3-methylbut-2-enyl)-8-(3-hydroxy-3-methylbut-1-enyl) xanthone] (5) and four known xanthones: mangostanaxanthones I (1) and II (2), γ-mangostin (3), and mangostanaxanthone VII (4) were separated and characterized from the acetone fraction of Garcinia mangostana L., Clusiaceae (mangosteen) pericarps. Their structures were established based on various spectroscopic analyses in addition to HRMS and comparison with the literature. The α-amylase inhibitory potential of the isolated metabolites was evaluated. Compounds 1, 2, and 5 had the highest activity with % inhibition 72.5, 86.5, and 81.8, respectively compared to acarbose (97.1%, reference α-amylase inhibitor). The molecular docking study of the tested metabolites was estimated to shade up the rational explanation of the α-amylase inhibitory activity results. Moreover, the pharmacokinetic parameters were assessed using Swiss ADME. It is noteworthy that 1, 2, and 5 had similar binding poses as the X-ray crystal structure of acarbose, whereas the other metabolites possessed different binding mode that decreased their inhibitory capacity. Thus, these data reinforced the health benefit of mangosteen as an alternative medicine to help lowering the postprandial glucose absorption. Therefore, it could have a good potential for the treatment of diabetes.

ABSTRACT Cyperus rotundus L. (Suada, Sueda, family: Cyperaceae) is vastly spread in several world's subtropical and tropical regions. It had variable traditional uses and bioactivities. A new flavonol derivative: cyperaflavoside (myricetin 3,3',5'-trimethyl ether 7-O-β-D-glucopyranoside) and five flavonoids: vitexin, orientin, cinaroside, quercetin 3-O-β-D-glucopyranoside, and myrcetin 3-O-β-D-glucopyranoside were separated from the methanolic extract of C. rotundus aerial parts. Their structures were verified based on UV, IR, NMR (1D and 2D), HRESIMS, and comparison with literature. All metabolites were assessed for their 5-lipoxygenase inhibitory potential. All compounds possessed 5-lipoxygenase inhibitory potentials with IC50s 5.1, 4.5, 5.9, 4.0, 3.7, and 2.3 µM, respectively, in comparison to indomethacin (IC50 0.98 µM). These results supported the traditional uses of C. rotundus in treating inflammation and its related symptoms.

ABSTRACT A new ursane-type triterpene ester, plectraterpene [3β-(decanoyloxy)-19-hydroxy-urs-12-ene] and four known steroidal compounds have been isolated from the aerial parts of Plectranthus montanus Benth. (syn. Plectranthus cylindraceus Hochst. ex Benth.), Lamiaceae. The known compounds were stigmasterol, sitosteryl ferulate, cholest-5-en-3-O-β-D-glucopyranoside and stigmasterol-3-O-β-D-glucopyranoside. Compounds plectraterpene, sitosteryl ferulate and stigmasterol-3-O-β-D-glucopyranoside are reported for the first time from this plant whereas compound cholest-5-en-3-O-β-D-glucopyranoside first time from the genus. The structures of these compounds were determined through spectral analysis, including extensive 2D NMR data as well as chemical methods and comparison with literature.

ABSTRACTA new phenylethyl chromenone, cucumin S [(R)-5,7-dihydroxy-2-[1-hydroxy-2-(4-hydroxy-3-methoxyphenyl)ethyl]chromone] (1), along with five known compounds: 5,7-dihydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone (2), 5,7-dihydroxy-2-[2-(3,4-dihydroxyphenyl)ethyl]chromone (3), luteolin (4), quercetin (5), and 7-glucosyloxy-5-hydroxy-2-[2-(4-hydroxyphenyl)ethyl]chromone (6) were isolated from the EtOAc fraction of Cucumis melo var. reticulatus Ser., Cucurbitaceae, seeds. Their structures were determined by spectroscopic means (1D and 2D NMR), as well as HRESIMS, optical rotation measurement, and comparison with literature data. The isolated compounds 1–6 were assessed for their antioxidant activity using DPPH assay. Compounds 3, 4, and 5 showed potent activities compared to propyl gallate at concentration 100 µM.